California State University San Marcos issued an alert Friday warning students that members of an unrecognized fraternity were being investigated for an alleged rape involving date-rape drugs in May and that Tau Kappa Epsilon’s social events could be dangerous.

“While all reasonable precautions are being taken by law enforcement, the university is advising students and all campus community members to consider carefully whether their presence at or near TKE social events and parties could place them in danger of sexual assault, date rape drugs, or similar illegal drug and/or alcohol use and abuse,” the statement said.

The warning, which was issued via email to students, faculty and staff and mailed out to parents and families, comes as students are moving into campus housing for the fall semester, which starts Monday.

The alert was issued under the Clery Act, a federal law that requires all colleges and universities that participate in federal financial aid programs to track and disclose information about crime on and near campuses, said university spokeswoman Margaret Chantung.

The reported rape, along with reports of other alleged criminal behavior that include hazing, victim and witness intimidation, harassment, vandalism, and providing illegal drugs and alcohol to minors, prompted the university to launch its own investigations.

CSUSM police consider these reports to represent “a potentially serious and continuing threat to student and others in the university community and that conditions may continue to exist that may pose a threat to the campus community in the future,” the university’s statement said.

The campus warning comes at a time when there’s growing national concern and debate about sexual assaults on college campuses and how administrators are responding.

“Monday is the first day of classes and we have students moving into on-campus housing today and we felt that it was not only the right thing to do but the legal thing to do to let students know there is this investigation and that they need to be aware of it so they can take measures to protect themselves,” Chantung said Friday.

She said the chapter of the Tau Kappa Epsilon fraternity, which also is known as The Kollege Experience, has not been recognized by the university since 2005. None of the fraternities or sororities at San Marcos have houses and there is no Fraternity Row.

University officials don’t have an official roster of members but believe about 30 students are associated with the group.

Despite its lack of standing with Cal State San Marcos officials, the TKE national organization had still been recognizing the group. On Friday, however, the international headquarters of TKE temporarily suspended the chapter pending an investigation, said spokesman Alex Baker.

“We learned about this today and have begun our investigation today,” Baker said.

The reported sexual assault occurred in May at an off-campus party in Oceanside, Chantung said. She said the Oceanside police are investigating the case, but have not made an arrest.

Oceanside Police Lt. Leonard Cosby said the woman identified the man she said assaulted her at a party attended by about 200 people and he has voluntarily provided a DNA sample, which is being tested. The man told police he was not involved in any way.

University officials also have received additional reports of sexual assaults purportedly involving fraternity members, which were said to have occurred on or near the university and at off-campus residences of members.

University officials said TKE lost its recognition as a student organization as a result of underage alcohol use and failure of the organization to maintain academic standing required of fraternities and sororities.

“I am appalled and deeply saddened by these reports. The safety and well being of our entire campus community is the highest priority for CSUSM,” President Karen Haynes said in a statement. “We will not tolerate nor ignore sexual assault and we will hold members of our campus community accountable for their actions.”

The university asks victims or people aware of illegal conduct related to the fraternity to report the incidents to the university, Oceanside police or the county Sheriff’s Department. A special hotline for students has been set up at (760) 750-7233, and reports can be made anonymously.

Bridget Blanshan, associate vice president for student affairs and Title IX coordinator, said the university sent the alert after its police determined there was an ongoing threat to students. She said it was the first such alert she could recall.

Every year, she said, the university also placed information on university websites that told students that TKE was not a recognized fraternity.

“We are under an obligation to make students aware so they can make informed decisions,” she said.

Blanshan said some parents had contacted the university after the warning was publicized and said they were happy the campus was taking a “proactive stance” in protecting students.

A website for the TKE chapter said it holds its members to a higher standard and does its part to improve the surrounding communities.

“Although no longer officially recognized by our university, we set the bar for academics and involvement, as our chapter holds one of the highest average GPAs,” the site said. It also said the chapter hosts some of the “most reputable nightlife experiences” that San Marcos and the surrounding community has seen.